If the D.C. planning office gets its way, developers in Washington soon could be allowed to build bigger buildings if they promise to provide social benefits for the city, such as job training for District residents, hiring minority contractors or building low-income housing.

Giving developers increases in building heights and density, known in planner parlance as "incentive zoning," has been used by many local governments to force developers to provide public amenities that make their developments more attractive, such as plazas, landscaping, historic preservation or superior design.

But a proposal now before the D.C. Zoning Commission could substantially expand the use of incentive zoning here by allowing developers to provide benefits addressing a wide range of social and economic problems that might have little to do with the project.

The proposed changes, which would loosen the regulations for "planned unit developments," are opposed by several citizens planning groups. They have said that the new regulations would allow for "spot zoning" and "undermine the integrity of the recently adopted Comprehensive Plan."

Developers and zoning attorneys, recognizing that such a change could create both opportunities for increased building densities and problems if the Zoning Commission becomes too demanding in requirements, are cautiously supportive.

The regulations for planned unit developments, known as PUDs, were designed to give developers greater flexibility with sites that pose special problems or needs, such as poor access, the need to accommodate historic buildings or to allow for other uses than those allowed in the zoning. Under a PUD, a developer often is allowed different and higher land uses than would be allowed under either the zoning for the site or a variance.

With the proposed changes, however, the Zoning Commission could use the PUD zoning category to exchange zoning value for social services. At the same time, the proposed changes would substantially reduce the minimum size for PUDs in many areas of the city, a move that neighborhood groups say could trigger extensive redevelopment in stable areas.

D.C. Planning Director Fred L. Greene, in a letter to the Zoning Commission July 2, recommended new language for the zoning regulations that would expand the type of public benefit that could be offered in exchange for higher zoning.

"Project amenities should not be limited to architectural amenities, but may include social and economic benefits such as sponsorship of job training and education programs, contractural agreements to ensure hiring of D.C. residents or contracting with minority firms and construction of housing units," Greene said.

Greene also included a recommendation that construction of housing as a suitable public benefit should not be limited to the subject PUD site, but could be built somewhere else in the city and still justify zoning increases on the PUD site. He also said that while off-site housing should be priced for low- and moderate-income tenants, that would not be necessary if the project were found to be a public benefit.

The proposed changes also call for a clause that would allow the Zoning Commission to award higher densities if the proposed project were, itself, "a high-priority use that may be an important public benefit and may be more important than amenities in a particular case."

"The combination of loosened guidelines or standards, smaller area size, and amenities expanded far beyond the range of zoning would take the Zoning Commission into an era of systematically instituting spot zoning and exceeding its authority to zone," said William Washburn III, chairman of the Citizens Planning Coalition in a letter to the Zoning Commission.

"I can think of no other recommendation that could be so sweeping as this," said Ann Hargrove, chairman for the coalition's committee on the Comprehensive Plan. She said that reduction in minimum size would open up all of the rowhouse neighborhoods to PUDs, through which developers could win the right to build commercial uses or apartment buildings in some predominantly rowhouse areas.

The current regulations do not allow PUDs on sites smaller than three acres in residential or industrial areas, with a small exception for areas zoned for very high-density apartment houses.

The proposal, however, would reduce that minimum to 15,000 square feet for any area of the city except the R1, R2 and R3 areas, which are those zoned for single-family detached or semi-detached houses and single-family rowhouses. The R4 areas, such Capitol Hill and Mount Pleasant, would be part of the city open to the smaller PUDs.

Fifteen thousand square feet is about one-third of an acre, or slightly more than eight contiguous rowhouse lots in the R4 zone. PUD sites in the R1-R3 areas would have to be a minimum of two acres.

In justifying the proposed size reductions, the planning office said that PUDs tend to result in a "higher quality of development" than results from the developers' allowable zoning or variances, and that the smaller minimums were necessary to allow planned unit development on the many small, in-fill sites in the city.

But the Citizens Planning Coalition contests the planning office's claim that PUDs lead to better development.

"Many community spokesmen, in reviewing the PUD record, would argue that these developments have undermined existing zoning protections by diminishing the housing supply, creating excessive densities and providing minimal amenities which are inadequate in comparison to the trade-off of a loss of use and density control," Washburn said. He also said that allowing PUDs on smaller sites would result in more fragmented development.

Richard Wolf, chairman of the planning committee for the Capitol Hill Restoration Society, criticized the proposal, saying that the planning office has not conducted any studies to support its proposal and that, in the case of some PUDs, the city has exchanged zoning increases for amenities that amount to little more than a fountain or a strip of landscaping.

"This proposal would open up a lot of the city to invidious spot zoning," Wolf said. "It gives the zoning commission the tools to make deals with the developers, in some cases -- such as minority hiring -- asking the developers to give amenities they would have to supply anyway under existing laws." Wolf also questioned whether the proposal would present an enforcement problem for the city in case developers did not fulfill their promises.

J. Kirkwood White, a zoning attorney with Linowes and Blocher, said that developers are "skeptical" about the proposal at this point, but that, with careful writing of the standards and the public hearing process required of most PUDs, the city could avoid problems of spot zoning. He also said that the city could enforce the agreements by refusing to issue occupancy permits for buildings built by developers who had not lived up to their promises.

"It's a legitimate concern that citizens would see this as a threat to their neighborhoods, but since everything is worked out on a case-by-case basis and negotiated between the Zoning Commission, there are sufficient controls," White said.

Whayne S. Quin, a zoning attorney with Wilkes, Artis, Hedrick and Lane, said that incentive zoning that embraces broader social concerns is becoming something of a trend, with several cities requiring developers to contribute to housing funds or build housing in exchange for increased zoning.

Quin said that in a recent PUD rezoning, one of his clients offered to build off-site housing as an amenity, arguing that the restrictions at the PUD site would prevent inclusion of housing in that mixed-use development.

Quin said the commission was interested, but rejected the proposal because the PUD regulations would not accommodate it.

Quin, however, cautioned the Zoning Commission against going "too far afield" with the authority to request a broader range of amenities, and said that the commission should get an opinion from the city's legal counsel about what it can and cannot do as a zoning body.

The Citizens Planning Coalition has also questioned whether the commission, in considering the changes, might be trying to extend its authority into the planning function that lies with the City Council. The coalition also has asked the commission to do studies on PUDs before adopting any changes.